The long term objective of this area of research is to develop non-invasive electrophysiological techniques to evaluate the peripheral and central pathways of the trigeminal nerve and apply these techniques to disorders such as trigeminal neuralgia, multiple sclerosis, and lesions along the sensory pathway of the trigeminal nerve. The purpose of this proposal is to visually describe (map) spatiotemporal voltage distributions of cephalic potentials evoked by electrical stimulation of the trigeminal nerve in normal subjects, to differentiate unilateral and bilateral voltage distributions, and to create a descriptive statistic database of spatiotemporal voltage distributions which can be used as normative values for comparison to various patient groups.